1. Field of the Invention
The present invention relates to slide fasteners, and more particularly to a watertight slide fastener.
2. Prior Art
There have been proposed many watertight slide fasteners comprising a pair of opposed waterproof stringer tapes and seal means for protection against water leakage between intermeshing rows of coupling elements mounted by extrusion molding on the respective stringer tapes along their inner longitudinal edges. Each stringer tape is composed of a woven or knit web having face and back layers of elastomer such as natural or synthetic rubber, and a sealing fin projecting from the longitudinal tape edge toward the coupling heads of companion coupling elements. When the slide fastener is closed and immersed in water, the sealing fins are brought into contact with the coupling heads, thereby hermetically sealing the intermeshing coupling elements against water leakage. In such slide-fastener closed position, those coupling elements received in a slider body, and the endmost coupling elements in particular, are however held out of mutual coupling engagement with each other with the result that water might pass through a space between the endmost coupling elements, thereby impairing watertightness of the slide fastener.